The main objective of this step is to remove the extreme edge of the spine, where the text block is held together by adhesive, and to leave the text block a stack of loose sheets of paper. Since this book has generous gutter margin, we are able to take a liberal amount (about 1 cm) off the text block and still leave plenty of margin. In the case of this book, this puts the cut inside the perforations left by the staples. Though not absolutely necessary, eliminating these perforations is desirable, if for no other reason that that they can make the task of jogging up the text block more difficult than it needs to be.